On Monday, Nov. 20, Saks Fifth Avenue will debut its iconic New York holiday windows and 10-story-tall theatrical light show in true fairytale fashion, in celebration of the 80th anniversary of Disney’s Snow White and the Seven Dwarfs. Sofia Carson, the multi-talented actress, star of Disney’s “Descendants”, and Hollywood Records/Republic recording artist, will perform live at the unveiling event accompanied by a 40-person choir and appearances by Snow White, Snow Prince, and the seven dwarfs. The fantastical new show, entitled Once Upon a Holiday, will include the…